Plate bending machines



Se t. 17, 1963 F. R. SAVORY PLATE BENDING MACHINES 3 Sheets-Sheet 1 Filed Feb 10, 1961 A Horn e yj P 7, 1963 F. R. SAVORY 3,103,965

PLATE BENDING MACHINES Filed Feb. 10, 1961 3 Sheets-Sheet 2 A tforney p' 7, 1963 F. R. SAVORY 3,103,965

PLATE BENDING MACHINES Filed Feb. 10, 1961 a Sheets-Sheet s WW AiZey;

United States Patent 3,103,965 PLATE BENDING MACHINES Frederick R. Savory, Sutton-in-Ashfield, England, as-

signor to Steel Construction & Engineering Co. (Notts.) Limited, Sutton-in-Ashfield, England Filed Feb. 10, 1961, Ser. No. 88,552 7 Claims. (Cl. 153-54) This invention relates to plate bending machines of the initial pinch type in which a tube is formed by bending and rolling a plate round a roll, which along with another roll is adapted to be driven and form a nip through which the plate is passed, a third roll being movable with respect to the first two rolls to effect first an initial bending of one edge of the plate fed to the nip from the side to which the third roll lies and then, after removal and reversal of the plate and feeding of the plate to the other side of the nip, the required bending of the rest of the plate.

The roll around which the tube is formed must be less in diameter than the required internal diameter of the finished tube, to allow for spring-back of the plate material after bending and, with the machine adapted to form a tube of small diameter in relation to its length, that roll is liable to bend axially under the stresses, with a consequent adverse eflfect on the straightness of the tube, whereas the other two rolls, not being encircled by the plate material may be of a suflicient diameter in relation to their length to withstand the bending stresses or, in the case of a very long machine, may be supported against bending at intervals along their length.

The object of the present invention is to provide an initial pinch plate bending machine of the type referred to having a small-diameter roll around which the tube is formed together with means for reducing to negligible proportions the bending of that roll.

According to the present invention, an initial pinch plate bending machine of the type refer-red to has the roll around which the tube is to be formed mounted with a stiff shaft parallel to it and at substantially the opposite side of the said roll to the side along which the bending stresses will be applied through the plate material by the other two rolls, and a pair of brackets non-rotatab1y mounted on the stiff shaft each carrying a pair of backing rollers to bear on the roll just beyond the ends of the tube to be formed, so as to transmit bending stresses from the said roll through the brackets to the stiff shaft. The stiffness of the stiff shaft thus provides added resistance against bending of the roll, which is particularly important when the roll diameter is very small, as when tubes of only a few inches bore are to be rolled. For example, the machine can be successfully used for rolling 4" diameter tubes from stainless steel plate. The other two rolls are not so restricted as to diameter, and can therefore be stiff enough to withstand the bending stresses arising from their operation.

Preferably, the brackets are adjustable lengthwise of the stiff shaft to enable the backing rollers to be set just beyond the ends of any tube length within the capacity of the machine. Thus the shaft may be cylindrical and provided with a lengthwise key or keys for engagement by corresponding keyways in journals in the brackets, and the journals may be split to enable the brackets to be clamped in adjusted position. Again, a square shaft may be used, to fit square holes in the brackets. The brackets may also be interchangeable with other similar brackets of a size suitable for a diflerent diameter of roll, in accordance with the diameter of tube to be formed.

Where, as is usual, one of the bearings for the roll around which the tube is to be formed is mounted in a swinging portion of the machine frame, to enable the Patented Sept. 17, 1963 bearing to be removed from the end of the said roll for endwise withdrawal of the formed tube from around the roll, there may be provided an adaptor arm adapted to fit in the swinging frame portion and carry both the removable bearing and an end support for the st-ifi shaft, so that the bearing and the end support may be removed together to permit withdrawal of the formed tube. Removal of the shaft support also permits the roller-carrying brackets to be removed from the shaft, e.g., for replacement, 1

Where, as is also usual, the other bearing for the roll around which the tube is to be formed is mounted rfor pivotal movement in the frame to enable the said roll to be swung away from the roll with which it forms the nip, there may be provided an adaptor arm adapted to fit in the pivotal mounting and carry the roll bearing for that end of the roll and the other end support for the shaft, with a lever arm extending from the adaptor arm to be operated by screw-gear after removal of the first adaptor arm to balance the mounting of the roll and the stiff shaft on the second adaptor arm.

With adaptor arms as described above at both ends of the roll around which the tube is formed, the roll may be interchangeably mounted in the bearings in the adaptor arms, for replacement of a worn roll or substitution of a roll of a different diameter. Again the whole unit of roll, shaft, brackets, adaptor arms and lever arm extension may be interchangeable for replacement by a similar unit of dimensions appropriate to a different range of tube diameters.

The invention will now be described with reference to the accompanying drawings, in which FIGURE 1 is a perspective view from one side of an initial pinch plate bending machine according to the invention;

FIGURE 2 is another perspective view of the machine from the same side but from the left-hand end of FIG- URE 1;

FIGURE 3 is a perspective view of the machine from the other side at the same end;

FIGURES 4 to 8 are diagrammatic end elevations of the bending rolls of the machine, showing the manner of operation;

FIGURES 9 and 10 are diagrammatic side elevations showing the forces involved in a conventional plate bending machine and a plate bending machine according to the invention, respectively; and

FIGURE 11 is a diagrammatic end elevation of a plate bending machine according to the invention, showing the angular disposition of the :forces involved.

In FIGURES 1 to 3, an initial pinch plate bending machine has end bearing housings 1, 2 spaced apart by side channels 3, which extend beyond the housing 2 to carry a main electric motor 4 for driving bottom and side bending rolls 5, 6, respectively, through a V-belt drive (protected by a casing 7) and bevel-gear and gear-and-pinion gearboxes 8, 9 respectively. The bottom roll 5 is mounted in bearing blocks 10 (only one of which is visible in the housing 1 in FIGURE 3) vertically adjustable in guide apertures 11 in the housings 1, 2 by means of manuallyoperable screw-gear 12, while the side roll 6 is mounted in bearing blocks 13 adjustable in inclined guide apertures 14 (also in the housings 1, 2) by means ofscrew-gear 15, which is operated by a reversible electric motor '16 through a gearbox 17, a chain-drive (protected by a casing 18) to a common shaft 19, and worm-and-pinion gearboxes 20 at the ends of the shaft. The housing 2 is also provided with bearing block 21, which is pivotable within an aperture 22 about a fixed horizontal and transverse axis 23, while the housing 1 is provided with a swinging portion 24 carried by a hinge 25 and normally held upright against the housing 1 by a locking pin 26 engaging eye-brackets 27, the top of the portion 24 being formed with a bearing aperture 28.

-All the parts that have just been described are to be found in conventional initial pinch plate bending machines (except that Where the screw-gear 15 is also manually-operable, in some machines, the motorised drive 16 20 is omitted). In addition, a conventional machine has a top roll 29 (FIGURE 9) mounted between the bearing aperture 28 and the pivotable bearing mounting 21, the top roll being driven from the bottom roll through pinions 30, 31, having deep teeth so as to remain in mesh throughout the range of adjustment of the vertical position of the roll 5 (as controlled by the screw-gear 12) available to suit the thickness of plate being bent. The roll 29 also has a lever arm 32 extending to screwdown gear 33 operable, after removal of the end bearing 28 by downward swinging of the housing portion 24, to swing the top roll 29 away from the bottom roll 5 for endwise withdrawal of the formed tube from around the roll 29.

A tube 34 (FIGURE 7) is formed from a plate 35 which is first fed over the side roll 6 and into the nip of the rolls 5 and 29 (FIGURE 4), to be held while the side roll 6 is moved with respect to the other rolls to eifect an initial bending of the edge 36 of the plate (FIGURE 5) into the required curvature, due allowance being made for springback of the plate material. The plate 35 is then removed and reversed, and fed into the nip of the rolls 5 and 29 from the opposite side (FIGURE 6). With the roll 6 in the same respective position as in FIGURE 5, formation of the tube 34 is completed by rolling as the rolls 5, 6, 29 are simultaneously driven.

FIGURE 8 shows how a tube 37 of smaller diameter than the tube 34 is rolled by bringing the side roll 6 closer to the top roll 29.

The rolls 5, 6 are of a sufi'icient diameter in relation to their length to withstand the bending stresses, but the roll 29-for forming tubes of small diameter in relation to their length-is liable to bend axially under the stresses, as shown in FIGURE 9, with a consequent adverse effect on the straightness of the tube. Whereas the rolls 5, 6 may be supported (in the case of a very long machine) at intervals along their length, the encircling of the roll 29 by the tube being formed, as well as its position remote from the base channels 3, makes it diificult to support that roll against the bending stresses.

In FIGURES 1 to 3, the roll 29 around which a tube 34A (FIGURE 1) is formed is rotatably mounted between the lower ends of a pair of adaptor arms 38, 39 and has a correspondingly shorter pinion 31A meshing with the pinion 30 of the roll 5, and the other ends of the adaptors are connected by a stifi fixed shaft 40, which carries a pair of support brackets 41 for the roll 29A. Each bracket 41 has a pair of transverse end plates 42 spaced apart by a short length of inverted T-section 43 and carries a pair of backing rollers 44 to bear on the roll 29A just beyond the ends of the tube 34A, so as to transmit bending stresses from the roll 29A through the plates 42 to the shaft 40 (FIGURES l0 and 11). The stiffness of the shaft 40 thus provides added resistance against bending of the roll 29A. The shaft 40 is provided with a lengthwise key 45 for engagement by keyways 46 in journals 47 in the end plates 42, to enable the brackets 41 to be adjusted lengthwise of the shaft 40 for the backing rollers 44 to be set just beyond the ends of any tube length within the capacity of the machine, and the journals are split at 48 to enable the brackets to be clamped in adjusted position by screws 49. The brackets 41 may also be interchangeable with other similar brackets of a size suitable for a different diameter of roll, in accordance with the diameter of tube to be formed. However, as is indicated by FIGURES 7 and 8, any top roll is suitable for a range of tube diameters, so that the top roll only requires changing when a range of lower order diameters is required.

The adaptor arm is provided with a spigot 50 to fit the bearing aperture 28 in the swinging portion 24 of the housing 1, when the portion 24 is in upright position, the adaptor arm 38 also being provided with a removable bearing 51 for the journal 51A of the roll 29A and a removable socket 52 for a spigot 52A on the end of the stiff shaft 40, normally secured by means of set-screws 53 and washers 54. The spigot 50 is tubular and has a cross-piece 55 Welded into its free end to serve as a handgrip, while a cut-away 56 provides accommodation for and affords access to the lower set-screw 53 and washer 54. The adaptor arm 39 is provided with a spigot 57 to fit the pivotable mounting 21, with a lever arm 32A extending from the spigot 57 to the screw-down gear 33, so that the roll 29A and stilt shaft 40 may be swuing upwardly, after downward swinging of the housing portion 24 away from the spigot 50, to facilitate removal of the adaptor arm 38 for endwise withdrawal of the formed tube 34A and/or interchange of the brackets 41. The other journal 58 of the roll 29 is removable endwise from a bearing 58A in the adaptor arm 39 for replacement of a worn roll by a new one of the same diameter or substitution of a roll of a different diameter, while the stiff shaft 40 is permanently secured by welding to the adaptor arm 39.

During rolling, the roll 29A is subjected not only to stresses arising from the nip with the roll 5 but also to stresses arising from bending of the plate by the roll 6 (see FIGURE 11), so that the axis of the stiff shaft 40 is required to be offset from the vertical plane through the axis of the roll 29A in order that the roller-carrying brackets 41 may have effect in substantially direct opposition to the resultant of the stresses applied through the plate material by the rolls 5, 6. The adaptor arms 38, 39 are held at the necessary angle by providing the arm 39 with projections 59, 60 respectively above and below the spigot 57, to fit in a vertical groove 61 in the pivotable mounting 21.

What I claim is:

1. An initial pinch plate bending machine of the type comprising a roll around which a tube is to be formed by bending and rolling a plate, a second roll for forming with the first roll a nip through which the plate is to be passed, means for driving the two rolls, and a third roll movable with respect to the first and second rolls for effecting first an initial bending of one edge of the plate fed to the nip from the side to which the third roll lies and then, after removal and reversal of the plate and feeding of the plate to the other side of the nip, the required bending and rolling of the rest of the plate, the machine being further provided with a stiff shaft, means for supporting the stiff shaft parallel to the first roll at substantially the opposite side of the first roll to the side along which the bending stresses will be applied through the plate material by the second and third rolls, a pair of brackets non-rotatably mounted on the stiff shaft, and a pair of backing rollers carried by each bracket to bear on the first rol-l just beyond the positions to be occupied by the ends of the tube to be formed, so as to transmit bending stresses from the first roll through the brackets to the stilt shaft.

2. An initial pinch plate bending machine as in claim 1, wherein the roller-carrying brackets are adjustable lengthwise of the stiff shaft, to enable the backing rollers to be set just beyond the positions to be occupied by the ends of a tube of any length within the capacity of the machine.

3. An initial pinch plate bending machine of the type comprising a roll around which a tube is formed by bending and rolling a plate, a second roll for forming with the first roll a nip through which the plate is to be passed, means for driving the two rolls, and a. third roll movable with respect to the first and second rolls for effecting first an initial bending of one edge of the plate fed to the nip from the side to which the third roll lies and then, after removal and reversal of the plate and feeding of the plate to the other side of the nip, the required bending and rolling of the rest of the plate, the machine being further provided with a stiff cylindrical shaft, means for supporting the stiff shaft parallel to the first roll at substantially the opposite side of the first roll to the side along which the bending stresses will be applied through the plate material by the second and third rolls, a pair of brackets, journals in the brackets for closely fitting on the stiff shaft, a lengthwise key on the stiff shaft, key-ways in the journals corresponding to the key on the stiff shaft, and a pair of backing rollers carried by each bracket to bear on the first roll just beyond the positions to be occupied by the ends of a tube of any length within the capacity of the machine, so as to transmit bending stresses from the first roll through the brackets to the stiff shaft.

4. An initial pinch plate bending machine as in claim 3, wherein the journals in the roller carrying brackets are split, and screws are provided for clamping the split journals on the stiff shaft with the brackets adjusted lengthwise of the stiff shaft for the backing rollers to bear on the first roll just beyond the positions to be occupied by the ends of a tube of any length within the capacity of the machine.

5. An initial pinch plate bending machine of the type comprising a frame, a roll around which a tube is to be formed by bending and rolling a plate, a second roll for forming with the first roll a nip through which the plate is to be passed, means at one end of the frame for driving the two rolls, a third roll movable with respect to the first and second rolls for effecting first an initial bending of one edge of the plate fed to the nip from the side to which the third rol1 lies and then, after removal and reversal of the plate and feeding of the Plate to the other side of the nip, the required bending and rolling of the rest of the plate, a bearing at the driving end of the frame for one end of the first roll, a swinging frame portion at the other end of the frame, and a removable bearing in the swinging frame portion for the other end of the first roll, the machine being further provided with a stiff shaft, means at the driving end of the frame for supporting one end of the stiff shaft at substantially the opposite side of the first roll to the side along which the bending stresses will be applied through the plate material by the second and third rolls, an adaptor arm removably mounted in the swinging frame portion, a removable hearing at one end of the adaptor arm for the other end of the first roll, means at the other end of the adaptor arm for supporting the other end of the stiff shaft with the stiff shaft parallel to the first roll, .a pair of brackets non-rotatably mounted on the stiff shaft, and a pair of backing rollers carried by each bracket to bear on the first roll just beyond the position to be occupied by the ends of the tube to be formed, the removable bearing permitting withdrawal of the formed tube from around the first roll after swinging of the swinging frame portion and removal of the said bearing.

6. An initial pinch plate bending machine of the type comprising a frame, a roll around which a tube is to be formed by bending and rolling a plate, .a second roll for forming with the first roll a nip through which the plate is to be passed, means at one end of the frame for driving the two rolls, a third roll movable with respect to the first and second rolls for effecting first an initial bending of one edge of the plate fed to the nip from the side to which the third roll lies and then, after removal and reversal of the plate and feeding of the plate to the other side of the nip, the required bending and rolling of the rest of the plate, a bearing at the driving end of the frame for one end of the first roll, a pivotal mounting for the bearing, a swinging frame portion at the other end of the frame, a removable bearing in the swinging frame portion for the other end of the first roll, a lever arm extending from the pivotal mounting, and screw-gear for operating on the free end of the lever arm, to balance the mounting of the first roll, after swinging of the swinging frame portion and removal of hte removable bearing to permit withdrawal of the formed tube from around the first roll, the machine being further provided with an adaptor arm removably mounted in the swinging frame portion, a removable hearing at one end of the adaptor arm for one end of the first roll, a stiff shaft, means at the other end of the adaptor arm for supporting one end of the stiff shaft at substantially the opposite side of the first roll to the side along which the bending stresses will be applied through the plate material by the second and third rolls, a second adaptor arm carried by the Pivotal mounting, a hearing at one end of the second adaptor arm for the other end of the first roll, means at the other end of the second adaptor arm for supporting the other end of the stiff shaft with the said shaft parallel to the first roll, a pair of brackets non-rotatably mounted on the stiff shaft, and a pair of backing rollers carried by each bracket to bear on the first roll just beyond the positions to be occupied by the ends of the tube to be formed.

7. [An initial pinch plate bending machine of the type comprising a frame, a roll around which a tube is to be formed by bending and rolling a plate, a second roll for forming with the first roll a nip through which the plate is to be passed, means at one end of the frame for driv-t ing the two rolls, a third roll movable with respect to the first and second rolls for effecting first an initial bending of one edge of the plate fed tothe nip from the side to which the third roll lies and then, after removal and reversal of the plate and feeding of the plate to the other side of the nip, the required bending and rolling of the rest of the plate, a bearing at the driving end of the fiame for one end of the first roll, a pivotal mounting for the bearing, a swinging frame portion at the other end of the frame, a removable bearing in the swinging frame portion for the other end of the first roll, a lever arm extending from the pivotal mounting, and screw-gear for operating on the free end of the lever arm, to balance the mounting of the first roll, after swinging of the swinging frame portion and removal of the removable bearing to permit withdrawal of the formed tube from around the first roll, the machine being further provided with an adaptor arm removably mounted in the swinging frame portion, a removable bearing at one end of the adaptor arm for one end of the first roll, a stiff cylindrical shaft, a removable support at the other end of the adaptor arm for supporting one end of the stiff shaft at substantially the opposite side of the first roll to the side along which the bending stresses will be applied through the plate material by the second and third rolls, a second adaptor arm carried by the pivotal mounting, a removable bearing at one end of the second adaptor arm for the other end of the first roll, means at the other end of the second adaptor arm for supporting the other end of the stiff shaft with the said shaft parallel to the first roll, a pair of brackets, split journals in the brackets for fitting the brackets on the'stiff shaft, 21 lengthwise key on said shaft, keyways in the journals corresponding to the key on the shaft, a pair of backing rollers carried by each bracket, and screws for clamping the split journals on the stiff shaft .with the brackets adjusted lengthwise of the still .shaft for the backing rollers to bear on the first roll just beyond the positions to be occupied by the ends of a tube of any length within the capacity of the machine.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN INITIAL PINCH PLATE BENDING MACHINE OF THE TYPE COMPRISING A ROLL AROUND WHICH A TUBE IS TO BE FORMED BY BENDING AND ROLLING A PLATE, A SECOND ROLL FOR FORMING WITH THE FIRST ROLL A NIP THROUGH WHICH THE PLATE IS TO BE PASSED, MEANS FOR DRIVING THE TWO ROLLS, AND A THIRD ROLL MOVABLE WITH RESPECT TO THE FIRST AND SECOND ROLLS FOR EFFECTING FIRST AN INITIAL BENDING OF ONE EDGE OF THE PLATE FED TO THE NIP FROM THE SIDE TO WHICH THE THIRD ROLL LIES AND THEN, AFTER REMOVAL AND REVERSAL OF THE PLATE AND FEEDING OF THE PLATE TO THE OTHER SIDE OF THE NIP, THE REQUIRED BENDING AND ROLLING OF THE REST OF THE PLATE, THE MACHINE BEING FURTHER PROVIDED WITH A STIFF SHAFT, MEANS FOR SUPPORTING THE STIFF SHAFT PARALLEL TO THE FIRST ROLL AT SUBSTANTIALLY THE OPPOSITE SIDE OF THE FIRST ROLL TO THE SIDE ALONG WHICH THE BENDING STRESSES WILL BE APPLIED THROUGH THE PLATE MATERIAL BY THE SECOND AND THIRD ROLLS, A PAIR OF BRACKETS NON-ROTATABLY MOUNTED ON THE STIFF SHAFT, AND A PAIR OF BACKING ROLLERS CARRIED BY EACH BRACKET TO BEAR ON THE FIRST ROLL JUST BEYOND THE POSITIONS TO BE OCCUPIED BY THE ENDS OF THE TUBE TO BE FORMED, SO AS TO TRANSMIT BENDING STRESSES FROM THE FIRST ROLL THROUGH THE BRACKETS TO THE STIFF SHAFT. 